1. Field of the Invention
The present invention relates to an air damper or door closer, and more particularly to an air damper or door closer including a simplified structure for reducing the manufacturing cost for the air damper or door closer and for allowing the air damper or door closer to be easily and quickly manufactured or assembled.
2. Description of the Prior Art
Typical air dampers or door closers or door shutting devices comprise a barrel or cylindrical housing, and a sliding rod or piston rod slidably received or engaged in the barrel or cylindrical housing and slidable between an outwardly extended working or extending position and an inwardly received storing position, and one or more spring biasing members disposed or attached or mounted or engaged into the cylindrical housing and secured or coupled between the cylindrical housing and the piston rod for recovering the piston rod back to the original position.
For example, U.S. Pat. No. 5,157,806 to Wartian, U.S. Pat. No. 5,220,7065 to Bivens, U.S. Pat. No. 5,313,739 to Nelson et al., U.S. Pat. No. 5,471,708 to Lynch, U.S. Pat. No. 5,706,606 to Lin, and U.S. Pat. No. 5,829,508 to DeBower et al. disclose several of the typical air dampers or door closers or door shutting devices each also comprising a sliding rod or piston rod slidably received or engaged in a barrel or cylindrical housing for damping or resisting the sliding movement between the cylindrical housing and the piston rod, and one or more spring biasing members disposed or engaged into the cylindrical housing and secured or coupled between the cylindrical housing and the piston rod for recovering the piston rod back to the original position.
However, the typical air dampers or door closers or door shutting devices include a complicated structure that may not be easily and quickly manufactured or assembled.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional air dampers or door closers or door shutting devices.